1. Field of the Description
The present invention relates, in general, to techniques for forming a contoured or non-planar substrate or structure that can be used for rear projection (RP) such as the eyes or other portions of an animatronic or robotic character, and, more particularly, to a method of fabricating an object with a rear projection (RP) substrate or RP screen element that may be contoured or dimensional and is integrally formed with an adjacent structural substrate(s) or a non-projecting element(s) of the object. For example, the method may be used to form an RP screen element that provides animated eyes of an animatronic character or creature when light and/or images are projected upon rear surfaces of the RP screen element.
2. Relevant Background
There are many applications where it is useful to provide a rear projection or RP screen within an assembled product. For example, theme parks may provide animatronic creatures and characters in show portions of theme rides or on floats of a parade. To make the creatures and characters come to life it is desirable for their eyes and their other body parts to move.
While it is useful to use mechanical assemblies to move many body parts, robotic-type eyes may seem unrealistic and “give away” the robotic nature of the creature or character. Many designers of animatronics or robotics have, as a result, begun to animate or bring life to eyes through the use of rear projection. In use, an animatronic character's eyes can be provided with one or more RP elements and one or more projectors that project still or video images displaying still or moving eyes. The video projection may be timed or synchronized, for example, with the moving of the head, mouth, and so on or to follow a person observing the character to effectively bring the character to life.
The RP element or substrate can limit the quality of the resulting projection in a number of ways and fabrication of objects or characters with RP substrates has presented difficulties that have not yet been fully addressed. Presently, the fabrication process of such a character involves forming a support structure for the RP elements and then attaching the RP elements. The support structure, for example, may be all or a portion of a character's face or head, and openings or holes will be provided or later cut out of this face or head to provide a place to attach the RP elements. The RP elements are separately formed and then carefully applied to the face or head, and then the projector is positioned within the face or head for use in projecting on the rear surface of the RP elements.
While the above steps may be labor intensive so that they are relatively costly and time consuming, more significant problems with fabrication of the object with RP substrates typically arise in the production of the RP substrates themselves. The RP substrates are typically arcuate or contoured in overall shape (e.g., non-planar) and also have to be formed with particular optical qualities to provide a good RP screen.
To this end, the RP substrate is typically formed using a multi-step process that includes first forming a clear or substantially transparent base substrate or layer such as through vacuum forming with a translucent to transparent plastic. The base substrate typically will have at least one curved or non-planar surface (e.g., a portion of a sphere) or may be thought of as a three-dimensional (3D) surface, but the substrate also preferably has uniform thickness to provide uniform transmission of light. Unfortunately, vacuum forming often provides a product that has varying thickness, and this leads to repeated attempts (or a trial and error-type process) to generate a more uniform thickness base substrate, which increases the time and cost to provide each base substrate. In a typical run, it is has been found that up to 80 percent of the parts have to be rejected due to unacceptable variance in the substrate thickness.
Additional problems arise in the final processing of the base substrate to provide the RP substrate. A typical next step is to apply an RP coating onto the rear or inner surface of the base substrate. The RP coating acts to provide the desired optical properties to the RP substrate such that light providing still and video images are effectively projected via the RP substrate (similar to an RP screen in a movie theater). The RP coatings presently in use are very expensive (e.g., up to $600/gallon), and it may require several coatings to achieve a desired result such as particular optical qualities. Further, the RP coating materials are typically toxic and special spraying facilities or equipment may be required for their use.
The spraying or application process can be complex and challenging, and it often can result in rejected parts due to non-uniformity or flaws in the RP coating layer (e.g., one drip of the RP coating in one of the two or more applications can produce an undesirable RP substrate). These challenges have typically required that manufacturers of animatronic/robotic characters or other objects with RP substrates send the base substrates out to another company (or division) for application of the RP coating, which further adds to the fabrication timeline and increases overall costs.
Hence, there remains a need for an improved method of fabricating RP substrates or elements for use in objects or devices that make use of RP systems to display imagery. Preferably, such a method would reduce the time and/or cost required to fabricate the RP substrate and, therefore, the object or RP assembly that includes the RP substrates. The method also may be selected or designed to better provide uniform optical qualities across or throughout each RP substrate produced by the method (e.g., a more uniform thickness of material(s)).